Bat forming apparatus and method



Nov. 25, 1952 c. G. JoA

BAT FORMING APPARATUS AND METHD 2 SHEETS-SHEET 1 Filed Sept. 28, 1949 C. G. JOA

BAT FORMING APPARATUS AND METHOD Nov. 2.5, 1952 2 SHEETS- SHEET 2 Filed sept. 28, 1949 elo 0.0 6,0 9a 0.0 o6 04o v A 00 oo o0 0.o 0.o 0,0 0.o 0.0 n 5.o 5.a

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Patented Nov. 25, 1952 UNITED STATES PATENT OFFICEl BAT FORMING APPARATUS AND METHOD Curt G. Joa, Sheboygan Falls, Wis.

Application September 28, 1949, Serial No. 118,357

27 Claims. l

This invention relates to a bat forming apparatus, method and product.

It is a primary object of the invention to provide improvements in bat formation to facilitate separation of fibrous material from pneumatic currents by which it is conveyed to the point of deposit; to provide a construction in which irregularities in manufacturing operations are automatically accommodated by self-equalization of various factors and changes in the point of bat formation within a range of self-adjustment which is sufficiently extensive to meet conditions encountered in practice; to preclude the clogging of a screen upon which the bat is formed by making portions of such screen fixed, and other portions relatively movable; to provide improved means for laterally confining the material on the screen to produce a bat with sharply dened lateral margins; to regulate, if desired, the rate of pneumatic projection of the material onto the bat at the point of bat formation; and to produce a bat having novel characteristics peculiarly adapting such bat for the blanking of sanitary napkin pads therefrom.

'Ihese and other objects of the invention will be more particularly explained in connection with the accompanying drawings, wherein:

Fig. 1 is a view partially in side elevation and partially in section showing bat forming mechanism embodying my invention.

Fig. 2 is a fragmentary detail view in longitudinal section through a modied delivery end portion of the embodiment shown in Fig. 1.

Fig. 3 is a detail view in perspective of a set of successive air aspirating nozzles used for the pneumatic delivery of the bat forming material to the point where the bat is formed.

Fig. 4 is an enlarged view in longitudinal section through a pair of bat forming conveyors used in the embodiment of Fig. 1.

Fig. 5 is a view taken in transverse section on line 5 5 of Fig. 4.

Fig. 6 is a fragmentary detail View in plan of the delivery end portion of the conveyor set shown in Fig. 4.

Fig. 7 is a greatly enlarged fragmentary detail view in perspective showing portions of an air separating conveyor screen.

Fig. 8 is an enlarged detail View in perspective of a sanitary napkin pad blanked from a bat made in accordance with the present invention.

Fig. 9 is a cross sectional view taken on the line 9-9 of Fig. 8.

A web Ill of sheet pulp stock derived from a parent roll II is delivered through the feeder I2 into the hammermill or other disintegrator I3 Where the pulp fibers are separated in the usual manner.

The blower I4 has its inlet connected with the disintegrator I3 by means of pipe I5 which leads from the bottom of the hammermill into the eye of the blower. The tangential discharge pipe i6 of the blower leads into one or more aspiratingnozzles I1, I8, I9 which progressively widen and flatten the stream of air and entrained fiber. As clearly appears in Fig. 3, the inlet to the rst nozzle is circular, being slightly larger in diameter than the pipe I6. The outlet from the nozzle I 'I may be of reduced vertical dimension but increased lateral dimension as indicated at 29 in Fig. 1. The delivery end 2l of the nozzle I9 is relatively broader and flatter. It is found that such a succession of nozzles, each of which takes in some'external air, enables the air stream to be made very wide and thin without clogging. Presumably, the additional air admitted around each of the nozzles, and drawn in by the aspirating effect of the convection current traversing the nozzle, floats the fiber and tendsA to keepit from contact with the wall of thenozzle, thus eliminating friction of the fiber against the wall.

From the final nozzle there issues a convection current which is not only thin, but is so wide as to extend for a substantial portion of the width of the entire bat forming screens. These screens are of novel construction, as best shown in Figs. 4 to 7. Each screen comprises a series of parallel stationary bars 22 which extend longitudinally of the bat in which the pulp fiber isprojected between upper and lower series of such bars. Spanning the bars to complete a grid or screen are the longitudinally spaced, transversely extending cross members 23, these being preferably half-round as best shown in section in Fig. 7. The flat faces 24 of the half-round or semielliptical rods 23 ride on the margins of the longitudinal bars 22. The opposite ends of thehalfround rods 23 are conveniently provided with chain link elements 254 which are pivotally connected to constitute conveyor chains operating over sprockets 26. These sprockets are mounted on cross shafts 21 and 28 respectively, these shafts being carried in brackets 29 and 30 at opposite sides of the machine frame. The cross rods 3I carry the respective longitudinally extending bars 22. The bars with which the cross rods of the upper conveyor are associated preferably converge upon the bars of the lower conveyor toward the delivery end of the machine, the centers of the sprockets for the conveyor chains being farther apart at the receiving end than at the delivery end, as is clearly shown in Fig. 4.

Within the flights of each conveyor there is a vacuum box, the upper vacuum box being desig-4 nated in Fig. 4 and Fig. 5 by reference character 33, and the lower vacuum box by reference character 34. The respective vacuum boxes are desirably provided with flat margins 35 such as may be formed by outwardly turning a ange as best shown in Figs. 5 and '7. Each conveyor has means cooperating with the other conveyor for laterally closing the space in which the bat is formed between the conveyors. One way of accomplishing this is to mount on each of the half-round rods 24 a closure block 36 having a vertical flange 31 and a horizontal ange 38. Inrectilinear movement between the conveyor sprockets, the successive blocks are in end contact as shown 1n Fig. 7. Their horizontal anges ride on the anges 35 of the respective vacuum box, while their vertical flanges lap in substantial face contact as best shown in Fig. 5, thereby coniining the material against lateral displacement so that the bat formed by the deposit of berin the space between the upper and lower conveyors has a sharply defined margin.

The iiber blown into the space between the upper and lower conveyors through the discharge end 2I of nozzle I3 will 'have sufficient velocity-so that it will tend to issue from the delivery .ends of `the -upper and lower conveyorsunlessits movement is impeded-by striking previously deposited material. Accordingly, to initiate the operation of the machine, I place pulp, rags, ber, paper, or any other material between the conveyors at some point near the delivery end thereof to close such end. The sides are already Vclosed by the lapping iianges .31 of the closure blocks 35. Accordingly, a mat of fiber is immediately deposited upon the upper and lower screens provided by the .crossing of rthe transverse rods 24 and the longitudinal bars 22. The Aconvection air escapes through the `grid provided by :the .rods and bars, these being sufficiently close 'together so vthat 'no appreciable vamount of fiber escapes.

The conveyors are,'of course, in operation, preferably at identical speeds, with the lower night of the upper conveyor andthe upper 'flight of the lower conveyor moving from right to left as viewed in Rigs. 1 and 4. If the cross members forming the grids or screens were fixed, they would soon :become clogged. Due, however, tothe fact that the longitudinalmembers are fixed, and the transverse vmembers move with the pulp, the conveyor screens clear `themselves and will function indefinitely without clogging.

YIt is only necessary to correlate the rate of conveyor movement With the average rate at which fibrous material is supplied. In practice, there is considerable kvariation in the rate at which pulp is delivered `from the hammermill. There may be normal accumulations within the hammermill, r there may be intervals, as during the replacement of a supply roll, when no pulp is delivered. All of these fluctuations will be accommodated during the functioning of the apparatus by the fact that the ber may accumulate asa bat anywhere along a substantial path of travel of the conveyors Which cooperate to form the screening chamber. If the ,supply of ber is unduly light, the advance `of the conveyors may carry the point of bat formation almost to the delivery end of the screening chamber without affecting the result. If, on the other hand, the supply of ber is temporarily heavy, the rate of conveyor movement may be inadequate to carry away the completed bat as fast as the ber is deposited, and the point of deposit will thereupon creep rearwardly toward the `inlet end of the machine. Again, the nature of the bat is substantially unaffected, and during continued operation, many such variations can occur,v and correct themselves, without requiring the attention of an operator.

The vacuum boxes 33 and 34 are provided with outletpipes 330 and 34D which communicate with a centrifugal separator or cyclone 39 (Fig. l). Oneorr more blowers 40 receive the air from the vacuum boxes and discharge it through the pipe 4I tangentially into the cyclone. Excess air issues Ythrough the usual center vent 42, and the ber -Which passes through -the screens of the bat forming chamber is returned from the bottom of the cyclone through pipe 43 to the hammerrnill 0r other disintegrator I3, where it is .mixed with any arriving ber and returned to the bat forming chamber.

As distinguished from a closed circuit for the air, the circuit herein described has important advantages in self-equalization of ow. It will be noted that the blower I4 which initially picks up the ber from the disintegrator I3 has no sourceof convection air other than 'the discharge pipe 43 from the cyclone `39. This is contrary to usual cyclone practice, wherein only solids are discharged from the bottom of the cyclone. To the rextent that the amount of air reaching Athe cyclone through pipe 4I is inadequate to supply the demands of blower I4, the cyclone will actually take in air through the pipe 42, instead of releasing air through such pipe in accordance with conventional practice. On the other hand, if there is an excess of air arriving through pipe 4I, which is more than adequate to supply the demands of blower I4, the excess escapes through the pipe 42. There may normally be an 'excess due to the aspirating effect of the nozzles I'I, Iy I9 as above described, which use the kinetic energy of air set in motion by the blower -I4 to aspirate more air into the system. The condition varies, however, during operation in the machine, and the pipe 42 of the cyclone separator 39 is sometimes an air inlet, yand sometimes an air outlet, the flow automatically adjusting itself to the demands of the apparatus.

I have found that the automatic regulation of air flow achieved in the manner above described is a very important feature, tending `to prevent the escape of ber from the bat forming chamber, and tending to promote uniformity in the bat deposited in such chamber. I have found that it is very important that the fiber be drawn by suction onto the upper and lower conveyor screens, since any pressure in the bat forming chamber tends to cause the ber to escape therefrom, With the device properly operating in the manner above described, the ber arrives with a pneumatic current, but the boxes nevertheless preclude the building up of any pressure in the chamber in which the bat is formed, and the automatic inward and outward breathing of the air through the pipe 42 of cyclone 39 maintains this condition.

The fact that the respective screen-forming conveyors at the top and bottom of the bat forming chamber are convergent toward the delivery end of such chamber tends to compress the newly formed bat, which issues from between the conveyors in a condition somewhat more dense than would otherwise be the case. Fig. 1 shows at 45 the nished bat delivered onto a conveyor 46 and engaged beneath a-conveyor 41 which delivers it beneath the blanking die 48, whereby finished sanitary napkin pads 50 are cut and discharged onto the delivery conveyor 5I. Due to the form and staggered location of the upper and lower conveyor cross rods 23, the finished bat 45,

' while of substantially uniform thickness, has

a wavy or convoluted form. This form also appears in the finished pad 50 as is clearly shown in Figs. 8 and 9, there being longitudinal ribs 52 alternating with longitudinal channels or troughs 53 which are staggered on the upper and lower surfaces. These are of particular service in4 sanitary napkin pads, since they tend to distribute longitudinally of the pad the secretions which the pad is designed to absorb. In the past, attempts have been made to achieve such distribution by compacting longitudinal portions of the pad, or by treating the pad along longitudinal lines with some relatively non-absorbent material. In both cases, the absorbency of the pad has been rendered non-uniform. Through the present invention, the absorbent characteristics of the pad are uniform in all portions, and yet longitudinal distribution of bodily secretions is encouraged.

Fig. 2 shows a modified arrangement in which the lower flight of the upper conveyor 55 and the upper night of the lower conveyor 56 are parallel rather than convergent, and the end sprockets 51 are arranged in pairs instead of using single sprockets for each conveyor. In this device, the operation is exactly the same as above described, except that no compression is achieved within the bat forming chamber. If bat compression is desired, the bat is delivered between laterally confining plates such as that shown at 510 and upper and lower belts, such as those shown at 5B and 59 which converge between the pulleys B0 and 6l; 62 and 63. If it be desired to laminate tissue plies with the pulp bat, tissue webs may be fed in over the belts 58 and 59 from supply rolls E4 and 65 respectively, the tissue webs being designated by reference characters 66 and 61 respectively, It is, of course, not essential that the tissue webs be fed onto the conveyor `belts 58 and 59. Fig. 2 shows an additional tissue web 68 delivered for lamination onto the pulp bat from a supply roll 69 over a pulley 10 beneath which the bat passes.

I claim:

1. A device of the character described comprising spaced screens dening opposite sides of a bat forming chamber, vacuum chambers for withdrawing air through said screens, a circulatory air convection system leading from said vacuum chambers and comprising a terminal delivery nozzle directed into the bat forming chamber between said screens, said air convection system including a cyclone, a fan taking air from the delivery end of the cyclone and between the cyclone and nozzle, means for delivering ber into the air admitted to said fan from the cyclone, and at least one additional fan between one of said vacuum chambers and said cyclone, both of said fans being provided with means operating them in a direction to propel air through said system, the said cylone having an outlet normally functioning for the escape of air but adapted to admit air for the operation of said iirst fan as required.

2. A device of the character described comprising a bat forming chamber having spaced screens, a nozzle arranged to discharge into said chamber between said screens, a convection ian having its delivery end connected with the nozzle, a pulp disintegrator with which the inlet to said fan communicates, a cyclone having a tangential inlet and a rst passage communicating with the atmosphere and a second passage communicating with said disintegrator, a second fan having its delivery end communicating with the tangential inlet of the cyclone, and vacuum box means associated with a screen of the bat forming chamber and with which the inlet of said second fan communicates.

1 In a device of the character described, Vthe combination with a bat forming chamber comprising a screen, ofv a pneumatic conveyor discharging into said chamber and comprising a fan and meansl for supplying the fiber to the air set in motion by said fan, together with a vacuum box connected with said screen and provided with air evacuating means for withdrawing air from said bat forming chamber through said screen, said air evacuating means having a discharge connection communicating with said pneumatic conveyor for the return thereto of at least a portion of the air discharged by said pneumatic conveyor into said bat forming chamber and discharged from said bat forming chamber through said screen and vacuum box.

4. The device of claim 3 in which said bat forming chamber screen comprises relatively nxed, longitudinally extending members and relatively movable, transversely extending members, the said members together constituting said screen, and the transversely extending members having driving links mutually connected to comprise a conveyor for the delivery from said bat forming chamber of a bat formed therein.

5. The device of claim 4 in which the relatively movable, transversely extending members comprise rods having iiat faces and arcuate faces, the relatively xed members comprising bars having edges along which the dat faces of said rods move in bearing contact.

6. In a device of the character described, the combination with a convection conveyor nozzle, of a bat forming chamber comprising spaced sets of bars extending longitudinally away from said nozzle and mutually spaced laterally in the respective sets, and conveyors comprising transverse rods spaced longitudinally of said chamber and seated upon the respective bars to constitute grids for screening bat material from convection air.

'7. The device of claim 6 in further combination with means for delivering air to said nozzle, said means comprising another nozzle spaced from and directed into the nozzle iirst mentioned, the rst mentioned nozzle having a delivery end which is wider and thinner than the delivery end of the nozzle discharging into it.

8. The device of claim 6 in further combination with vacuum boxes for withdrawing air through the respective grids provided by said bars and the rods of the respective conveyors.

9. The device of claim 8 in further combination with a circulatory system of air conduits leading from said vacuum boxes back to the nozzle and including a cyclone having two discharge ports, one of which opens to atmosphere, and another of which communicates with said nozzles, said conduits including air circulating means between the vacuum boxes and the cyclone and between said other cyclone outlet and said nozzles, together with means for introducing iiber into said system between said cyclone and nozzles.

10. In the device of the character described, the combination with a bat forming chamber comprising opposed conveyors, each constituting screening means, of side iianges connected with each of the respective conveyors, the flanges connecting to one conveyor lapping the anges connected to the other conveyor to provide sides for said chamber.

1l. In a device of the character described, a bat forming chamber comprising laterally spaced, longitudinally extending bars in opposed series, a conveyor associated with each series of bars and comprising transversely disposed 'rods riding on the respective bars and constituting therewith opposed screen grids and sprocket means for the support and operation of the respective conveyors.

12. The device of claim 11 in which the said rods are provided at their ends with links in pivotal connection with each other to constitute chains operable over said sprocket means.

13. The device of claim l2 in which the respective rods are provided with flanges lapping across the space between said series of bars whereby to provide side closures for the bat forming chamber.

14. The device of claim 13 in further combination with vacuum boxes disposed at opposite sides. of the respective series of bars to withdraw air from the bat forming chamber, the said flanges having portions riding along the margins of said boxes to effect a seal therewith.

15. A bat forming chamber comprising opposed, movable, foraminous walls, said walls having staggered, transverse ribs projecting from said walls toward said chamber, whereby a bat formed between such walls will be convoluted with transverse ribs and channels mutually oset on its respective faces.

16. A bat forming chamber comprising opposed sets of laterally spaced, longitudinally extending bars and a conveyor associated with each such set and comprising longitudinally spaced, laterally extending rods disposed transversely of the chamber and riding on the edges of said bars, said bars and rods comprising grids for the escape of air from said chamber and the support of fiber therein.

17. The device of claim 16 in which the rods have substantially flat faces riding on the bars and arcuate faces presented to the interior of the chamber, the rods of one conveyor being oifset from the rods of the other conveyor, whereby said staggered rods mold in convolutions a bat formed in said chamber.

1S. A method of making a sanitary napkin pad which comprises molding a web of brous material and forming transverse convolutions in said web, and blanking pads transversely from such web, whereby the convolutions of the web extend longitudinally of the blanked pads.

19. A method of making sanitary napkin pads which'comprises the deposit of fiber to form a bat and the substantially continuous advance of the bat, while continuing to deposit ber at the rear of the advancing bat, and molding the deposited fiber as the bat is formed to provide transversely extending channels in the bat without affecting bat density.

20. The method recited in claim 19 followed by the further step of blanking sanitary napkin pads transversely from the bat, whereby the channels molded in the bat extend longitudinally of such pad.

21. The method of claim 19 in which the bat is subjected to progressively increasing pressure in the course of its advance during manufacture.

22. A method of pneumatically projecting brous material through a wide, flat nozzle which comprises the pneumatic projection of the material into the nozzle and the aspiration of additional air free of such material along the surfaces of the nozzle to reduce friction between the nozzle and the pneumatically conveyed material.

23. A method of separating pneumatically conveyed material from the convection current in 'which such material is delivered, said method comprising directing a convection current bearing pneumatically conveyed material into a conned space between opposed screens having relatively movable portions, and advancing relatively movable portions of said screens with such material independently of other portions of said screens.

24. The method of preventing the clogging of a screen which has crossing longitudinal and transverse members and which is used to separate fibrous material from a convection current, said method comprising the progressive advance with such material of the transverse members of the screen while the longitudinal members thereof remain stationary.

25. A method of making a sanitary napkin pad which comprises molding a web oi brous material and forming convolutions in a surface of said web, and blanking pads from said web with the said convolutions disposed intermediate the pad margins and extending longitudinally of the Dad.

26. A nozzle structure for pneumatically projecting fibrous material, comprising a first nozzle having an intake portion substantially circular in cross section and converging to an outlet portion substantially rectangular in cross section, and a second nozzle having a substantially rectangular intake portion embracing the outlet portion of said first nozzle and converging to a substantially rectangular outlet portion of greater lateral extent than the outlet portion of the first nozzle, whereby a pneumatic stream through said nozzle structure will be gradually changed from circular to rectangular cross section, the intake portion of said second nozzle being peripherally spaced from the outlet portions of said first nozzle to communicate with the atmosphere whereby the pneumatic stream within the nozzle will aspirate additional air into the second nozzle through said space and about the stream to reduce friction between the said second nozzle and the pneumatically conveyed material.

27. A nozzle structure for pneumatically projecting the brous material and comprising a rst nozzle having an intake portion and an outlet portion, and a second nozzle having an intake portion embracing the outlet portion of the rst nozzle, said intake portion of said second nozzle being peripherally spaced from the outlet portion of the said first nozzle to communicate with the atmosphere whereby the pneumatic stream within the nozzle will aspirato additional air into the second nozzle through said space and about the stream to reduce friction between the said second nozzle and the pneumatically conveyed material.

CURT G. JOA.

REFERENCES CITED The following references are of record in the ile of this patent:

UNITED STATES PATENTS Number Name Date 1,961,272 Williams June 5, 1934 2,016,401 Thomas Oct. 8, 1935 2,020,319 King Nov. 12, 1935 2,079,094 Whitehead et al May 4, 1937 2,131,808 Joa Oct. 4, 1938 2,195,158 Watts Mar. 26, 1940 2,282,477 Joa May 12, 1942 2,289,250 Denning July 7, 1942 2,294,899 Fourness et al Sept. 8, 1942 2,295,439 Voigtman Sept. 8, 1942 2,325,975 Pearce Aug. 3, 1943 

